Effects of microplastics on wastewater and sewage sludge treatment and their removal: A review

Biogas from anaerobic digestion processes: Research updates

Biogas production through syntrophic acetate oxidation and deliberate operating strategies for improved digester performance

Anaerobic digestion of food waste: A review focusing on process stability.

This review aims at providing a unified methodology for free ammonia nitrogen (FAN) calculation in anaerobic digesters, also identifying the factors causing the huge disparity in FAN inhibitory limits. Results show that assuming ideal equilibria overestimates the FAN concentrations up to 37% when compared to MINTEQA2 Equilibrium Speciation Model, used as reference. The Davies equation led to major improvements. Measuring the concentrations of NH4+, Na+ and K+ was enough to achieve major corrections. The best compromise between complexity and accuracy was achieved with a novel modified Davies equation, with systematic differences in FAN concentrations of 2% when compared to MINTEQA2. Applying this modified Davies equation, data from the literature (1590 data points from over 50 scientific studies) were used to recalculate FAN inhibitory limits using a clustering approach. This procedure allowed to link inhibition resilience with operational conditions and microbial communities, providing also generalized values of inhibitory constants. The results showed that pH and temperature are the main factors affecting FAN inhibition, with thermophilic systems having a higher resilience towards FAN inhibition. The clustering results showed that Methanosaeta-dominated reactors have the lowest resilience towards FAN, verifying the relatively low inhibition limits for acetoclastic archaea. Mixotrophic Methanosarcina dominated at intermediate FAN concentrations, being more resistant than Methanosaeta but less resilient than hydrogenotrophic archaea. Methanoculleus appeared as the most resilient methanogen. This article provides general guidelines for accurate FAN calculation, explaining also how FAN resilience relates to the operational conditions and the microbial communities, underlying the importance of microbial adaptation.

Unraveling the literature chaos around free ammonia inhibition in anaerobic digestion

Tolerance response to in situ ammonia stress in a pilot-scale anaerobic digestion reactor for alleviating ammonia inhibition.

A model based on feature objects aided strategy to evaluate the methane generation from food waste by anaerobic digestion.

Anaerobic co-digestion has been considered to be a promising energy-producing process for kitchen waste and excess sludge treatment. However, the investigation of the hydrolysis performance is still required for further improvement of this process. In this study, the results indicated that the co-digestion model can enhance the system stability during hydrolysis phase. The pH of the co-digestion group remained stable at 6.94–7.18, which had a better buffer capacity compared to the kitchen waste and excess sludge group. The maximum value of dehydrogenase activity was 949 TF μg/(L h) in the co-digestion group, 105% and 30% higher than that in the kitchen waste and excess sludge group, respectively. The protease activity in the co-digestion group reached a maximum of 2.705 U/mL at 4.5th hour, which increased by 94.3% and 46.8% than in the kitchen waste and excess sludge group, respectively. The fitting curve correlation coefficient (R2) of the kinetic model was over 0.997 in three groups, and the generation ...

Evaluation of the hydrolysis performance in the kitchen waste and excess sludge anaerobic co-digestion process

The invention discloses a method for producing methane by carrying out anaerobic digestion on kitchen waste and belongs to the field of organic solid waste treatment control and environment-friendly purifying treatment technology. The method has the advantages that the highest methane yield is 1049.85mL/gTS when the inoculation ratio, solid content and initial pH are 2.42, 8.62% and 8.49 respectively, and the highest methane yield is 1085.8mL/gTS when the inoculation ratio, solid content and initial pH are 2.66, 8.06% and 8.87 respectively.

Method for producing methane by carrying out anaerobic digestion on kitchen waste

The invention discloses a method for analyzing a process of producing methane from kitchen wastes by applying a lactic acid modified ADM1, and belongs to the technical field of organic solid waste treatment. An anaerobic digestion process of the kitchen wastes is analyzed by adopting the lactic acid modified ADM1, and model parameters are optimized. A root-mean-square error and an absolute error of a methane yield theoretical value and a practical yield calculated by adopting the modified ADM1 are both smaller than 10%; R2 reaches 0.981; an assessment result is accurate; and the process of producing the methane from the kitchen wastes can be well predicted.

Meijuan Yu

Papers

Tolerance response to in situ ammonia stress in a pilot-scale anaerobic digestion reactor for alleviating ammonia inhibition.

A model based on feature objects aided strategy to evaluate the methane generation from food waste by anaerobic digestion.

Evaluation of the hydrolysis performance in the kitchen waste and excess sludge anaerobic co-digestion process

Method for producing methane by carrying out anaerobic digestion on kitchen waste

Method for analyzing process of producing methane from kitchen wastes by applying lactic acid modified ADM1